Developmental and cytogenetic assessments of preimplantation embryos derived from in-vivo or in-vitro matured human oocytes
Fesahat, F.; Kalantar, S.M.; Sheikhha, M.H.; Saeedi, H.; Montazeri, F.; Firouzabadi, R.D.; Khalili, M.A.
European Journal of Medical Genetics 61(4): 235-241
Aneuploidy is of great relevance to embryo selection, as it represents one of the important causes of implantation failure. Furthermore, immature oocytes, retrieved during gonadotrophin-stimulated IVF cycles, are generally discarded in clinics; whereas, there was no detectable comprehensive evidence on higher rates of aneuploidy based on maturity status on the day of oocyte retrieval. As well, the correlation between embryo morphology on aneuploidy remains unclear. The aim was to evaluate the developmental and genetic integrity of human preimplantation embryos from rescue in-vitro matured MII stage oocytes as well as in vivo matured oocytes. 541 rescue in-vitro matured oocytes as case as well as 659 in-vivo matured oocytes as control were used for the developmental assay. Finally, 121 cleaved embryos with good quality were analyzed by FISH technique for the detection of chromosomes X, Y, 13, 15, 16, 18, 21 and 22. The fertilization rates were 61.62% and 61.76% in case and control groups, respectively. Also, embryo formation rates of 89.1% vs. 92.2% were recorded for case and control groups, respectively. Good quality embryos on day 3 were 62.54% in case and 68.36% in control groups. There were insignificant differences in fertilization, embryo formation and quality between the groups. Total abnormality in 35 of the 60 embryos was 58.5% in case and 62.3% in control (p < 0.05). There were significant differences between aneuploidy rates of embryos using only sex chromosome preimplantation genetic screening (PGS) and sex chromosome in combination with autosomal chromosomes PGS in case (58.5% vs 28.3%, p = 0.000) and control groups (62.3% vs 21.3%; p = 0.000). The results demonstrated that a high proportion of good quality embryos were aneuploid in both patient groups with no obvious increase in aneuploidies as a result of rescue IVM application. Furthermore, the morphological characteristics of embryos do not completely consistent with chromosomal content. Despite the Rescue IVM is currently not a routine procedure in association with IVF, our finding suggested a viable option for young infertile women facing cancellation of their IVF treatment due to ovarian over-response or resistance factors as well as patients with low functional ovarian reserve considering good quality of embryos from rescue IVM-MII oocytes.